Monolithic transformers are used in on-chip radio frequency (RF) integrated circuits (ICs) to perform a range of functions including impedance matching, signal coupling and phase splitting. Monolithic transformers provide a number of advantages for the circuit designer over conventional transformers including lower power consumption and higher packaging density. Monolithic transformers enable power amplifiers to be fabricated by standard CMOS processes.
However, there are issues with transformers. For example, they might have low self-resonant frequencies, high mis-match between the coils and trade-offs between performance and silicon area consumption.
Therefore, challenges for exploring more efficient transformers exist.